diff --git a/doc/manual.html b/doc/manual.html
index 3b52eac..cf25ff7 100644
--- a/doc/manual.html
+++ b/doc/manual.html
@@ -601,7 +601,7 @@ panel_size = 94% 30
 <li><p><code>execp_cache_icon = boolean (0 or 1)</code> : If <code>execp_cache_icon = 0</code>, the image is reloaded each time the command is executed (useful if the image file is changed on disk by the program executed by <code>execp_command</code>). <em>(since 0.12.4)</em></p></li>
 <li><p><code>execp_icon_w = integer</code> : You can use <code>execp_icon_w</code> and <code>execp_icon_h</code> to resize the image. If one of them is zero/missing, the image is rescaled proportionally. If both of them are zero/missing, the image is not rescaled. <em>(since 0.12.4)</em></p></li>
 <li><p><code>execp_icon_h = integer</code> : See <code>execp_icon_w</code>. <em>(since 0.12.4)</em></p></li>
-<li><p><code>execp_tooltip = text</code> : The tooltip. Leave it empty to not display a tooltip. Not specifying this option leads to showing an automatically generated tooltip with information about when the command was last executed. <em>(since 0.12.4)</em></p></li>
+<li><p><code>execp_tooltip = text</code> : The tooltip. If left empty, no tooltip is displayed. If missing, the standard error of the command is shown as a tooltip (an ANSI clear screen sequence can reset the contents, bash: <code>printf '\e[2J'</code>, C: <code>printf(&quot;\x1b[2J&quot;);</code>). If the standard error is empty, the tooltip will show information about the time when the command was last executed. <em>(since 0.12.4)</em></p></li>
 <li><p><code>execp_font = [FAMILY-LIST] [STYLE-OPTIONS] [SIZE]</code> : The font used to draw the text.  <em>(since 0.12.4)</em></p></li>
 <li><p><code>execp_font_color = color opacity</code> : The font color. <em>(since 0.12.4)</em></p></li>
 <li><p><code>execp_markup = boolean (0 or 1)</code> : If non-zero, the output of the command is treated as Pango markup, which allows rich text formatting. The format is <a href="https://developer.gnome.org/pygtk/stable/pango-markup-language.html">documented here</a>. Note that using this with commands that print data downloaded from the Internet is a possible security risk. <em>(since 0.12.4)</em></p></li>
diff --git a/doc/tint2.1 b/doc/tint2.1
index 4fa82b8..7ab5982 100644
--- a/doc/tint2.1
+++ b/doc/tint2.1
@@ -716,7 +716,7 @@ To hide the clock, comment \fB\fCtime1_format\fR and \fB\fCtime2_format\fR\&.
 .IP \(bu 2
 \fB\fCexecp_icon_h = integer\fR : See \fB\fCexecp_icon_w\fR\&. \fI(since 0.12.4)\fP
 .IP \(bu 2
-\fB\fCexecp_tooltip = text\fR : The tooltip. Leave it empty to not display a tooltip. Not specifying this option leads to showing an automatically generated tooltip with information about when the command was last executed. \fI(since 0.12.4)\fP
+\fB\fCexecp_tooltip = text\fR : The tooltip. If left empty, no tooltip is displayed. If missing, the standard error of the command is shown as a tooltip (an ANSI clear screen sequence can reset the contents, bash: \fB\fCprintf '\\e[2J'\fR, C: \fB\fCprintf("\\x1b[2J");\fR). If the standard error is empty, the tooltip will show information about the time when the command was last executed. \fI(since 0.12.4)\fP
 .IP \(bu 2
 \fB\fCexecp_font = [FAMILY\-LIST] [STYLE\-OPTIONS] [SIZE]\fR : The font used to draw the text.  \fI(since 0.12.4)\fP
 .IP \(bu 2
diff --git a/doc/tint2.md b/doc/tint2.md
index 38586e9..66ece25 100644
--- a/doc/tint2.md
+++ b/doc/tint2.md
@@ -591,7 +591,7 @@ The action semantics:
 
   * `execp_icon_h = integer` : See `execp_icon_w`. *(since 0.12.4)*
 
-  * `execp_tooltip = text` : The tooltip. Leave it empty to not display a tooltip. Not specifying this option leads to showing an automatically generated tooltip with information about when the command was last executed. *(since 0.12.4)*
+  * `execp_tooltip = text` : The tooltip. If left empty, no tooltip is displayed. If missing, the standard error of the command is shown as a tooltip (an ANSI clear screen sequence can reset the contents, bash: `printf '\e[2J'`, C: `printf("\x1b[2J");`). If the standard error is empty, the tooltip will show information about the time when the command was last executed. *(since 0.12.4)*
 
   * `execp_font = [FAMILY-LIST] [STYLE-OPTIONS] [SIZE]` : The font used to draw the text.  *(since 0.12.4)*